Technical Field
The present invention relates to a borate bioactive glass and method of use in dental restoration and bone grafting.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Treatment of dentin hypersensitivity is one of the major problems faced by dentists worldwide. See Orchardson R, et al., J Am Dent Assoc., 137, 990 (2006)—incorporated herein by reference in its entirety. Moreover, dental caries are one of the most prevalent diseases in the world. See Bakry A S, et al., J Dent., 42, 1458 (2014)—incorporated herein by reference in its entirety. Many agents have been employed for the treatment of both problems; however, more research is needed to explore more options for providing advantageous solutions for these challenges.
Dentin hypersensitivity results from a loss of the overlying enamel coronal tissues by non-cariogenic processes, combined with the subsequent exposure of the underlying dentin tissues to the oral cavity. See Bakry A S, et al., J Dent Res., 90, 246 (2011)—incorporated herein by reference in its entirety. This condition causes exposure of a large number of fluid-filled dentinal tubules to the oral cavity. The hydrodynamic theory of dentin hypersensitivity is the most widely accepted explanation of the condition, and is based on the movement of these fluids. For example, a sudden change in temperature or pH in the oral cavity may result in a rapid movement of these dentinal fluids, and this rapid movement causes the activation of nerve fibers located in close proximity to the odontoblastic cells. These cells are present in the deepest portions of the dentinal tubules, and it is the activation of these nerve fibers that causes the feeling of sharp pain when a patient with dentin hypersensitivity drinks fluids having different temperatures and/or pH. See Brannstrom M, et al., J Dent Res., 47, 679, (1968)—incorporated herein by reference in its entirety.
Based on the current research and clinical observation, the most successful strategy to treat dentin hypersensitivity is to block the orifices of the dentinal tubules exposed to the oral cavity, in order to stop the fluid movement within the dentinal tubules. See Bakry A S, et al., J Dent Res., 90, 246 (2011) and Bakry A S, et al., Dent Mater., 29, 357 (2013)—each incorporated herein by reference in its entirety. However, the available methods and agents employed for the treatment of dentin hypersensitivity have only temporary effects due to their poor efficiency both in blocking the dentinal tubules and in resisting various harsh conditions of the oral cavity for long durations. See Bakry A S, et al., Dent Mater., 29, 357 (2013)—incorporated herein by reference in its entirety.
On the other hand, dental caries result from the dissolution of the enamel surfaces by the action of bacterial acids. These bacterial acids come from dental bacterial biofilms colonized on the enamel surface. See Bakry A S, et al., Dent Mater., 30, 314 (2014)—incorporated herein by reference in its entirety. Loss of dental enamel tissues even in extremely small amounts cannot be compensated by dental tissues or cells because the embryonic enamel forming cells (i.e. the ameloblasts) are completely lost during the eruption of the teeth. See Bakry A S, et al., Dent Mater., 30, 314 (2014)—incorporated herein by reference in its entirety. This unique developmental characteristic of the dental enamel tissue makes its repair only feasible using artificial filling materials. The most successful currently available materials used for dental enamel repair are resinous materials. These resinous materials have long un-polymerized hydrocarbon chains which can polymerize and attain significant mechanical properties upon being applied to replace the defective enamel tissues. The major chemical differences between the coronal dental tissues (enamel and dentin) and the available resinous materials used for the restoration of the lost enamel and dentin tissues leads to the inevitable failure of the interface between the resin materials and the dental tissues. Many attempts have been conducted to use materials having the same chemical composition of teeth to restore them in vitro; however, most of these attempts were difficult to be applied clinically.
The first type of bioactive glasses was introduced by Professor Larry Hench in the 1960s and was called 4555 Bioglass. This bioactive glass has the ability to form a hydroxyapatite rich layer capable of interacting with hard and soft tissues. See Hench L L, et al., J. Am. Ceram. Soc., 74, 1487 (1991)—incorporated herein by reference in its entirety. Since then, bioactive glasses have been mainly used in the field of orthopedics and periodontology. See Hench L L, et al., J. Am. Ceram. Soc., 74, 1487 (1991); Hulbert S. F. et al., Ceramics in clinical applications: Past, present, and future., Elsevier, Amsterdam, The Netherlands, 1987; and Yamamuro T. et al., Handbook of Bioactive Ceramics, Vol. II: Calcium Phosphate and Hydroxylapatite Ceramics. CRC Press, Boca Raton, Fla., 1990—each incorporated herein by reference in its entirety. Literature has focused on the use of various compositions of bioactive glasses on bone and soft tissues; however, there has been only scant information about the possible application of the bioactive glasses on enamel and dentin. See Bellucci D, et al., Mater Sci Eng C Mater Biol Appl., 51, 196 (2015); Bretcanu O, et al., J Tissue Eng Regen Med. 3, 139 (2009); Hu S, et al., J Mater Sci Mater Med., 20, 281 (2009); Stahli C, et al., Acta Biomater., 19, 15 (2015); and Mao C, et al., Biomed Mater., 10, 025005, (2015)—each incorporated herein by reference in its entirety. Our research team has reported excellent results using 45S5 Bioglass to restore incipient caries lesions and to remineralize subsurface demineralized lesions. 4555 Bioglass may have further application as a potent desensitizing agent capable of treating dentin hypersensitivity symptoms by occluding the dentinal tubule orifices of dentin. See Bakry A S, et al., J Dent, 42, 1458 (2014); Bakry A S, et al., J Dent Res., 90, 246 (2011); Bakry A S, et al., Dent Mater., 30, 314 (2014); and Bakry A S, et al., J Dent., 39, 599 (2011)—each incorporated herein by reference in its entirety.
In view of the foregoing, one objective of the present invention is to provide borate bioactive glass particles, and a paste that may be made from those particles and used to restore a dentin layer or an enamel layer on a surface of a tooth.